DISEASES OF PLANTS. 539 



of combating this fungus, a three years' succession of wheat, corn, and sor- 

 ghum is recommeuded. Aeration of the soil by deep fall plowing has also been 

 found effective. 



A new type of bacterial disease, E. F. Smith (Science, n. ser., 38 (1913), 

 No. 991, p. 926). — A brief description is given of a disease of orchard grass 

 formerly described by Rathay (E. S. K., 11, p. 759). This disease is of bac- 

 terial origin and the growth first develops as a thick layer on the surface of 

 the plant, later penetrating into the interior. It is proposed to call the organ- 

 ism, which has been isolated, Aplanobacter rdthayi n. sp. 



Diseases affecting potatoes, M. T. Cook (Attn. Rpt. N. J, Bd. Affr., 40 {1912), 

 pp. 155-161). — Besides a brief discussion of the various potato diseases infest- 

 ing or threatening this section, with known or suggested renietlies, the author 

 proposes the organization of a potato growers' association for the State with 

 a view to protecting this crop from disease in New Jersey. 



Report on the prevalence of potato blight in Ireland up to mid-July, 

 1913 (Dept. Agr. and Tech. Instr. Ireland Jour., 13 {1913), No. 4, pp. 732- 

 73.'t). — It is stated that while potato blight was reported from different counties, 

 the disease showed no tendency to spread rapidly. Outbreaks were confined 

 chiefly to early varieties, owing probably to the backwardness of the crop, 

 favorable weather, and more general spraying. Investigations are reported 

 as still in progress regarding black stalk rot, stalk disease, and yellowing, 

 which in recent years have caused considerable injui-y to the potato crop, 

 especially in the west of Ireland. 



Spra3ring tests against potato blight, G. Quinn {Jour. Dept. Agr. So. Aust., 

 n {1913), No. 3, pp. 301-306). — Giving results of several series of experiments, 

 a number of which were contradictory and inconclusive, the author states 

 that the history of the disease seems to Indicate that in very dry climates it is 

 problematical whether it pays in the long run of years to spray potatoes 

 against Irish blight if the crops be grown during the summer months. 



Further contribution to the study of Fusarium leaf roll of potato, W. 

 HiMMELBAUR (Ostcrr. TJngar. Ztschr. Zuekerindws. u. Landw., 42 {1913), No. 5, 

 pp. 711-736, pi. 1, figs. 8).— Further study (E. S. R., 28, p. 848) is claimed to 

 support the view that this disorder is due to a Fusarium. The varieties most 

 resistant to the attack were those which most quickly formed cork on wounded 

 surfaces. A temporary rolling of the leaves, it was found, may be produced 

 by injury to the vascular bundles. Wounding the lower portion of the stem 

 showed no considerable effect on the yield of tubers. 



The pathological anatomy of potato scab, B. F. Lutman {Phytopathology, 

 S {1913), No. 5, pp. 255-264, figs. iO).— Attention is called to the fact that most 

 of the studies on the potato scab have been concerned with methods of preven- 

 tion, and the author gives an account of his investigations on the pathology of 

 the disease. 



He finds that scabs may originate at any place on the potato, frequently oc- 

 curring at the lenticels. The scab is due to the hypertrophy of the cells of the 

 cork cambium. A surface view of the brown spots on the skin of scabby po- 

 tatoes and very young scabs show the thread-like filaments of the fungus which 

 apparently produces the disease. The carbon compounds stored in the diseased 

 tissues consist of a large number of fat globules instead of the usual starch 

 grains. 



The eflaciency of formaldehyde in the treatment of seed potatoes for 

 Rhizoctonia, W. O. Gloyer {New York State Sta. Bui. 370 {1913), pp. 417-431, 

 pi. 1). — The author investigated the relative efliciency of the standard scab 

 treatments in the disinfection of seed potatoes affected with Rhizoctonia, for- 



3S196°~No. 6—14 4 



